Method of producing alkyl esters of abietic acid



Patented Mar. 4, 1930 UNITED STATES PATENT. OFFICE ALAN C. JOHNSTON, OE KENV'IL, NEW JERSEY, ASSIGNOB TO HERCULES IPOWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION'OF DELAWARE METHOD OF PRODUCING ALKYL ESTERS F ABIE'IIC ACID Ho Drawing.

My invention relates -to the production of alkiy esters of resin acids, and more particular y contemplates the production of alkyl esters of abietic acid, through the use of alkyl halides.

In carrying out the process embodyin my invention the alkyl esters may be pro need by the esterification of resin acids in a pure.

state or as found in resins and by virtue of my invention the esters may be prepared for example, from ordinary wood rosin or rom a resin, for example, containing pimaric acid.

According-to my invention, for example, abietic acid or rosin is subjected to treatment with an alkyl halide, for example, an alk l chloride such as ethyl chloride, amyl chlori e, etc., or an akyl bromide, as ethyl bromide, butyl bromide, etc., in the presence of an alkali, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, etc., the alkali preferably being in solution in alcohol. The treatment of the abietic acid, or of rosin, in accordance with my invention is carried out at temperatures enabling refluxing and may 25 be earned out under atmospheric or increased prggsure depending upon the alkyl halide us v The process according to my invention more particularly involves the heating of abietic acid, orother resin acid, pure or as found in rosins or in resins, with an alkyl halide and suflicient alkali for neutralizing the abietic acid with the formation of ahalide of the,

alkali and the alkyl abietate. The-reaction is preferably carried out in the presence of a solvent, as an alcohol, which will dissolve both the alkyl halide and the inorganic abietate. When the reaction between the inorganic abietate, e. g. sodium resinate, and the akyl halide is complete, the inorganic halide formed is filtered off, the alcohol removed by distillation and the ester subsequently distilled off under reduced pressure. Any excess of the alkyl halide is recovered with the alcohol, both of which may be reused.

As examples of the carrying out of the process embodying my invention the follow- 111 will be illustrative a the production, for example, of ethyl imitates 1Q parts of sodium hydroxide are Application filed October 18, 1927. Serial No. 227,042.

dissolved in 325 parts of ethyl alcohol and 325 parts of rosin A. N. 170 are then dissolved in the solution. The solution is then heated with 75 parts of ethyl chloride for about one-- half hour in an autoclave under a pressure of about 160 pounds and at a temperature of about 150 C.-160 C. The reaction is as follows When the reaction,'which will require about one-half hour, is complete the sodium chloride which has been formed is filtered out the ester from a small amount of soda ash or by adding soda ash to the crude product from which the ester is originally distilled, prior to the distillation off of the ester.

As a further example of the carrying out of the process involving my invention, for ex- 8 ample, for the production of n-butyl abietate, 20 g. of sodium hydroxide are dissolved in 20 cc. of water and 200 parts of ethyl alcohol added. To the solution formed 150 g. of rosinand 100 g.-of butyl bromide are added and the whole refluxed for a period of six hours. When the reaction is complete the alcohol may be distilled off and then about g. of n-butyl abietate, A. N. 6, may be recovered by distillation under reduced pressure. 90

As a. further example, the n-amyl abietate may be prepared by forming a solution of 60 g. of sodium hydroxide and 750 parts of alcohol, then adding to the solution 450 parts of rosin and 200 parts of normal amyl chloride.- 5 The solution formed after being heated in an autoclave at say about 'C.-160 C. for about one hour and distillation off of the alcohol will yield by distillation under reduced pressure about 353 parts of n-amyl abietate A. N. 5. The n-amyl abietate will distill within the range of about 240 C.250 C. under mm. pressure. Mixed amyl chlorides, or a mixture of alkyl chlorides, e. g. butyl, amyl and hexyl chlorides may be converted into alkyl abietates in a similar manner.

It will be noted that in the carrying'out of the process embodying my invention the ab ietic acid, or resin acid, is substantially neutralized by treatment with .an alkali, forming an inorganic salt of the abietic acid, or other resin acid. As the alkali I prefer to use sodium hydroxide, but it will be understood that potassium hydroxide, sodium carbonate, calcium hydroxide, etc. may be used.

It will be noted in accordance with my invention that the production of abietates or esters of abietic acid, which may be relatively pure, or as found in rosin, may be prepared.

through the useof alkyl halides such as the alkyl chloride or the alkyl bromide. In addition to the methyl and ethyl esters of abietic acid the n-propyl, isopropyl, n-butyl, isobutyl and isoamyl esters may be produced. 5 Further, in accordance with my invention I have discovered the practicability of producing normal amyl abietate through the use of an alkyl halide, a compound which has not heretofore been known. It will be understood that while I have described the application of my invention more particularly to the production of abie+ tates, that my invention is applicable to and contemplates the treatment of other resin.

acidsas, for example, pimaric acid.

I have not herein claimed the amyl ester of a resin acid and the method of producing the same as such forms the subject. matter of an application for patent filed by me as a a division hereof, filed June 12, 1928, Serial Having now fully what I claim and desire to protect byLetters Patent is l of a resin'acid, which includes the step of treating a resin acid with-an alkyl halide inthe presence 'of an alkali and distilling ofi the ester formed under reduced pressure.

2. The method of producing an alkyl ester of abietic acid, which includes the ste of treating abietic acid with an alkyl hali. e in the presence of'an alkali and distilling olf the ester-formed under reduced pressure. ing ofi the ester formedunder) reduced.pres

3. The method of producing an alkyl ester of abietic acid, which includes heating a solution of abietic acid, an alkali and an alkyl halide and distilling oil? the ester formed 1111-.

der reduced pressure. 4. The methodof producing an alkyl ester of abietic acid, which includes subjecting abietic acid to treatment with an alkyl halide I in the presence oi alcohol and an alkali and distilling off the ester formed under reduced 66 pressure. Y

' formed under reduced pressure.

described my invention,

1.' The method of producing an alkyl ester' 5. The method of producing an alkyl ester of abietic acid, which includes subjecting sodium abietate to treatment with an alkyl halide and distilling off the ester formed.

, 6. The method of producing an alkyl esterof a resin acid, which includes subjecting a resin to treatment with an alkyl halide and alkali in the presence of a solvent for both the alkyl halide and the inorganic salt of the resin acid, separating the alkali halide formed from the solution of the ester formed and distilling off the ester.

7 The method of producing an alkyl ester of abietic acid, which includes subjecting sodium abietate to treatment with an alkyl halide in the presence of a solvent for both the alkyl halide and sodium abietate, separating the alkali halide formed from the solution of the ester formed and'distilling oil the ester under reduced pressure.

8. The method of producing an alkyl ester of abietic acid, which includes heating aninorganic salt of abietic acid with an alkyl chloride under pressure and distilling oil the ester'formed under reduced pressure.

9. The method of producing an alkyl ester of abietic acid, which includes heating abietic acid, an alkali and an alkyl halide under pressure and then distilling ofithe ester formed under reducedpressure. i 1

10. The method of producing an alkyl es: ter of abietic acid, which includes heating sodium abietate, an alkyl chloride and alcohol underpressure and distilling off the ester 11. The method of producing an alkyl ester of'abietic acid, which includesheating abietic acid, an alkali, and an alkyl halide under pressure in the presence of a solvent for both the alkyl halide and the ester to be produced, separating the alkali halide formed from the solution of the ester formed and distillingoif the ester under reduced pressure. I

12. The method of producing the ethyl ester of abietic acid, which includes the step of subjecting analkali metalsalt' of abieticacid to treatment with an ethyl halide and distilling oif the ester formed under reduced pressure: j 13. The method of producing the ethyl ester of abietic acid, which includes the step of subjecting an inorganic salt of abietic acid to treatment with ethyl chloride and distilllie sure.

n14. The method of producing the ethyl ester of abietic" acid, which includes heating a solution of abietic acid, an alkali and an ethyl halide 'and distilling ofl the ester formed under reduced pressure. I

15. The method of producingb the' ethyl ester of abietic acid, which includes subjecting abietic acidto treatment with anbth'yl halide in the presence of'aleohol and m and distillingofi the ester formed under reduced pressure.

16. The method of producing theethylester of abietic acid, which includes Sub ecting abietic acid to treatment with an ethyl halide and alkali while heating under pressure and distilling off the ester formed under reduced pressure.

17. The method of producing the ethyl ester of a resin acid, which includes heating a solution of a resin acid, an alkali and an of rosin, which includes heating a solution of rosin, an alkali and an ethyl halide and distilling off the ester formed under reduced pressure.

20. The method of producing the ethyl ester of wood rosin, which includes heating a solution of wood rosin, an alkaliand an ethyl halide and distilling ofi the ester formed under reduced pressure.

21. The method of producing an alkyl ester of wood rosin, which includes the ste of treating wood rosin with an alkyl hali e in the presence of an alkali and distilling off the ester formed under reduced pressure.

22. The method of roducing an alkyl ester of wood rosin, whlch includes subjecting wood rosin to treatment with an alkyl halide in the presence of alcohol and an alkali and distilling off the ester formed under reduced pressure.

23. The method of roducing an alkyl ester of wood rosin, whlch includes heatin an inorganic salt of wood rosin with an a chloride under pressure and distilling ofi e ester formed under reduced pressure.

24. The method of producing the ethyl ester of a resin acid which includes heatin to a temperature oii about (la solution of a resin acid, an alkali and ethyl chloride under pressure and then distilling oif the ethyl ester under reduced pressure.

25. The method of producing the ethyl ester of abietic acid which includes heating to a temperature of about 150 C.160 C. a solution of rosin, an alkali and ethyl chloride under pressure and then distilling ofl the ethyl ester under reduced pressure.

In testimony of which invention, I have hereunto set my hand, at Kenvil, New J ersey, on this 13th day of October, 1927.

- ALAN C. JOHNSTON. 

